Hydraulic fracturing or fracking is a process that involves injecting fluid at high pressure into subterranean rocks thereby creating openings, in the form of cracks, to allow the extraction of oil or gas.
In operation, fluid ends of a fracking pump are subject to localised high pressures because the fluid ends deliver high pressurized fluid into the impermeable layers of the subterranean rock such that the tensile strength of the impermeable layers is overcome and cracks form. The cracks penetrate the impermeable layers and therefore facilitate recovery of oil or gas from a gas/oil bearing formation located beneath the impermeable layers. As such, gases, such as methane can be retrieved and utilised.
Due to the extreme environment in which the pumps and fluid ends are utilised various studies have identified premature failure of the fluid ends due to fatigue cracking. Cracking is also affected by erosion and corrosion of the internal surfaces of the fluid ends. This has been identified particularly in fluid ends manufactured from 4330 steel.
It is desirable to improve material properties of components used in an extreme environment, for example to improve the effects of fatigue and stress corrosion cracking.
It is desirable to reduce the effects of fatigue cracking in fluid ends.